Fenestrated surgical drape and method of forming the same



D United States Patent [111 3,538,912

[72] Inventor Fred ll. Becks, [I] [56] References Cited -M UNITED STATES PATENTS P 755m 3,251,360 5/1966 Melges l28/l 32 [221 3 423 277 1/1969 Di ner 161/118 Patented Nu. w, 1970 p [73] Assignee American Hospital Supply Corporation Primary Examiner- Adele M. Eager Evanaton, Illinois Atiorney-Dawaon, Tilton, Fallon And Lungmus a corporation ofllllnols ABSTRACT: A fenestrated surgical drape formed of top and bottom layers of soft, porous and liquid-absorbent nonwoven cellulosic material and an intermediate barrier layer of thermoplastic material. Substantial areas of the respective sheets FENESTRATED SURGICAL DRAPE AND METHOD are unsecured to each other to define spaces therebetween for 0'' FORMING THE SAME the absorption and retention of liquid. in the immediate zone 10 ClllmlJ l I'- about the fenestration, the material of the barrier sheet extends into the pores of the cellulosic sheets or layers to bond [52] U.S.Cl. 128/132, all of the layers together in such zone. The fenestration is [ZS/I55, 156/290, 161/ l 18 formed by die-cutting the sandwiched sheets after they have [M] Int. Cl A61! 13/00 been compressed and secured together in the zone of at- (501 Field Search l28/l32, tachment so that the fenestration is defined by a clean sharp and reinforced edge portion.

Patented Nov. 10, 1970 ATT'Y FENESTRATED SURGICAL DRAPE AND METHOD OF FORMING THE SAME BACKGROUND In recent years nonwoven cellulosic material has found increasing use in the fabrication of surgical drapes. Drapes formed of such soft papers are relatively inexpensive and may be disposed of by incineration following use, thereby eliminating laundering costs and greatly reducing the possibilities of cross contamination.

While techniques are well known in the trade for making papers which are soft and clothlike in appearance and hand, such materials are unsuitable for use in the fabrication of surgical drapes unless they are subjected to a further treatment which renders them moisture resistant. Unfortunately, such treatment greatly reduces the softness of the papers and necessarily limits their ability to absorb or hold liquids in place. If the paper is given only a minimal moisture-resistant treatment in order to maintain the softness and absorbency of the product, then liquids may readily saturate the drape and, when so saturated, the drape no longer functions as a bacterial barrier. n the other hand, if the paper is given a more complete moisture-resistant treatment then the drape loses much of its softness and liquids spilling on to the drape tend to run off the treated surfaces thereof.

SUMMARY A main purpose of the present invention is to provide a fenestrated surgical drape which is soft, porous, and liquid absorbent but which, at the same time, will block the passage as such liquids completely through the drape. A further object is to provide a fenestrated drape which has a reinforced area or zone encircling the fenestration, the fenestration itself being defined by sharply-cut edges which do not present tiny fibers of cellulosic material which might otherwise project into the operative area, and which reduce the possibilities of wicking action about the periphery of the fenestration. A still further object is to provide a method for simply and easily producing such a drape.

These objects and advantages are achieved by providing a drape composed of upper and lower sheets of soft, porous, and liquid-absorbent nonwoven cellulosic material between which is disposed an intermediate barrier sheet of thermoplastic material. Aligned central openings are provided in all three sheets, and the material of the barrier sheet extends into the pores of the top and bottom sheets in an annular inner zone extending about such openings and secures all of the sheets together. Beyond such zone of interconnection, the sheets have substantial areas or zones which remain unsecured, thereby providing air spaces between the respective sheets in such outer zones.

The soft and porous outer sheets readily absorb liquid and, should the liquid-absorbing capacity of an area of the outer sheets be exceeded, such liquid may nevertheless pass into the spaces between the respective sheets. Such liquid cannot, however, pass directly through the drape because of the liquid-impermeable barrier of thermoplastic material.

Since air spaces are provided between the respective layers, the drape is a breathable" one despite the impermeable nature of the barrier layer. Thus, air may pass through the spaces between the paper layer in contact with a patient's skin and the thermoplastic layer thereabove, and since the paper layers are porous air may pass to and from the patient's skin through the drape. To promote such circulation of air, at least one of the side edges of the drape should be open; that is, the edge portions of the stacked layers should be unsecured to each other. To maintain the structural integrity of the drape, one or more of the other edges thereof may be secured together in a manner similar to that of the zone of attachment extending about the fenestration.

The drape is formed by positioning the layers upon each other and then heating and compressing a central area to soften the thermoplastic material in that area and to force it into the pores of the paper sheets or layers on opposite sides thereof. The three layers are thereby securely bonded together in a zone which will become the area of fenestration. At the same time, one or more edges of the drape may be similarly bonded together, it being preferable to bond only two parallel edges of the rectangular drape, leaving the layers unsecured along the remaining two edges for the reasons already expressed.

Thereafter, an opening or fenestration is die-cut in the central bonded zone. Since the paper layers have been previously compressed in that zone and since the thermoplastic layer at least partially impregnates the paper layers in such zone, a sharply die-cut edge may be formed to define the fenestration. The impregnation of the paper layers by the thermoplastic material in the zone immediately about the senestration tends to rein the paper layers in the bonded zone immediately about the fenestration lack the softness, absorbency, and fibrous character which is found in other areas of the paper sheets, the absence of these qualities immediately about the fenestration is a decided advantage. The annular mne about the fenestration is not only reinforced but, because of its reduced absorbency, tends to remain relatively free of liquids and, in view of the compaction of the paper sheets in that area, such sheets do not present fibrous material which might enter the wound.

DRAWXNGS FIG. 1 is a perspective view of the fenestrated surgical drape embodying the present invention;

P10. 2 is an enlarged fragmentary elevational view of the fenestrated area of the drape;

FIG. 3 is a still further enlarged sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a schematic view illustrating an early step in the method of forming the surgical drape;

FIG. 5 is a schematic view illustrating a later step in the fabrication of such drape.

DESCRIPTION Referring to the drawings, the numeral 10 generally designates a surgical drape of rectangular configuration. The drape is composed of top and bottom sheets l1 and 12 and an intermediate sheet 13. In the drawings, the sheets are bonded together along a pair of parallel side edge portions 14 and 15. While the remaining edges of the sheet may also be bonded together, they are preferably left unattached as indicated in FIG. 1.

The top and bottom sheets or layers 11 and 12 are formed of soft, porous and liquid-absorbent nonwoven cellulosic material. Such cellulosic material or paper is commercially available and, consequently, a detailed description of its properties and methods of manufacture is unnecessary herein. It is to be noted however, that such paper is preferably not surface treated to resist moisture penetration and, consequently, may be extremely soft and clothlilte in appearance and feel. it should, however, have high wet strength. Additional reinforcement of the paper, as by means of a scrim woven therethrough, is unnecessary and undesirable.

The intermediate barrier layer consists of a sheet of thermoplastic material which is imperforate (except for the central opening to be described hereinafter) and which is an effective barrier against liquid penetration. While any of a variety of flexible plastic films or sheet materials may be used, polyolefin films, particularly polyethylene, have been found especially effective.

Drape 10 has a central opening or fenestration l6 extending therethrough, the periphery of the fenestration defining the operative area in which surgery or treatment is to occur. The fenestration is defined by openings through each of the three superimposed sheets. An annular reinforcement zone 17 extends perimetrically about the fenestration, the three sheets of the drape being bonded together in such annular inner zone.

Beyond the periphery of that zone, as defined by the broken line 17a in FIGS. 1 and 2 is an outer zone 18 characterized by the absence of surface attachment between the respective sheets or layers. Since the sheets are highly flexible, air spaces l9 tend to be formed in the outer zone on opposite sides of thermoplastic barrier layer 13. Such spaces constitute passages for the circulation of air. Therefore, despite the fact that barrier film 13 is a "nonbreathing film, air may nonetheless pass to and from a skin surface covered by the outer zone of the drape because bottom sheet 12 is porous and its pores communicate with air spaces 19.

The drape is formed by superimposing or stacking three sheets 11-13 and then compressing a central area of such sheets between heating elements 20 and 21, as indicated in FIG. 4. By reason of such compression and heating, the thermoplastic material in the central zone is sottened and is at least partially forced into the pores of the paper sheets to bond such sheets together. At the same time, similar heating and compressing may occur along side edge portions [4 and 15. At least one side edge of the drape should be so bonded, and preferably a pair of opposite side edges, so that the drape will maintain its structural integrity. Thereafter, the aligned openings in the sheets are cut by dies 22 and 23 (FIG. to define fenestration 16. Since the sheet materials are already bonded together in the area or zone of die-cutting, the fenestration will be defined by a sharply-cut edge.

The result is a surgical drape which is highly absorbent to liquids while at the same time effectively blocks the passage of such liquids therethrough. The blocking action results from barrier layer 13 but, despite the fact that such layer provides an effective barrier not only against liquids but also against gases, the drape is nevertheless a breathable one for the reasons previously expressed.

While in the foregoing l have disclosed an embodiment of the invention in considerable detail for purposes of illustration, it will be understood by those skilled in the art that many of these details may be varied without departing from the spirit and scope of the invention.

I claim:

l. A fenestrated surgical drape comprising top and bottom sheets of soft, porous, and liquid-absorbent nonwoven cellulosic material; a barrier sheet of thermoplastic material between said top and bottom sheets; and aligned openings in said top, bottom, and barrier sheets; the material of said barrier sheet extending into the pores of said top and bottom sheets in an annular inner zone extending about said aligned openings and securing all of said sheets together in said inner zone to form a reinforced fenestration in said drape, said barrier sheet being unsecured to said top and bottom sheets in an outer zone extending about said inner zone; whereby, air spaces are provided in said outer zone between said sheets.

2. The structure of claim I in which said drape is generally rectangular in configuration.

3. The structure of claim 2 in which said sheets are secured together along at least one edge portion of said drape in a zone of attachment wherein said material of said barrier sheet extends into the pores of said top and bottom sheets along said zone of attachment and secures said sheets together therealong.

4. The structure of claim I in which the respective sheets are of substantially identical dimensions.

5. The structure of claim I in which said thermoplastic material is a polyolefin.

6. The structure of claim 5 in which said polyolefin is polyethylene.

'7. A method of forming a liquid-absorbent nonpermeable fenestrated drape, comprising the steps of positioning a sheet of flexible and imperforate thermoplastic material between a pair of sheets of soft, porous, and liquid-absorbent nonwoven cellulosic material, then heating and compressing a central area of the stacked sheets to soften said thermoplastic material in said zone and to force into the pores of said nonwoven cellulosic sheets to bond said sheets together in said area while at the same time leaving the sheets unsecured to each other in zones beyond said central area, and thereafter die-cutting an opening in said bonded area to provide a fenestration defined by sharply cut edges of compacted sheet material.

8. The method of claim 7 in which there is the additional step of heating and compressing edge portions of said sheets to soften said thermoplastic material along said edge portions and to force it into the pores of said nonwoven cellulosic sheets to bond said sheets together along said edge portions.

9. The method of claim 8 in which said additional step is performed on edge portions of said sheets along a pair of opposite side edges of said drape.

10. The method of claim 7 in which said thermoplastic material is a polyolefin. 

